README.md

Init Containers

Init Containers
Tips and Tricks

For simulated Practice problems visit KillerCoda.

1. Create a namespace demeter.

   Solution

   k create ns demeter

2. In demeter namespace create a pod named stew with an init container named setup with busybox image. Run another container named serve with nginx image.

   Solution

   apiVersion: v1
   kind: Pod
   metadata:
     creationTimestamp: null
     labels:
       run: stew
     name: stew
     namespace: demeter
   spec:
     initContainers:
       - image: busybox
         name: setup
     containers:
     - image: nginx
       name: serve
     dnsPolicy: ClusterFirst
     restartPolicy: Always
   status: {}

3. Take stew pod created from demeter namespace, there exist a yaml file pod.yaml for reference & use. create a volume named storage in the stew pod of type emptyDir. Mount storage volume on initContainer at path /set and run a command in init container echo "this is nginx index page" > /set/index.html. Mount same volume in nginx container at path /usr/share/nginx/html. Do these updates in pod.yaml. Delete & create the pod again

   Solution

   apiVersion: v1
   kind: Pod
   metadata:
     creationTimestamp: null
     labels:
       run: stew
     name: stew
     namespace: demeter
   spec:
     initContainers:
       - image: busybox
         name: setup
         command: ["sh","-c","echo 'this is nginx index page' > /set/index.html"]
         volumeMounts:
           - name: storage
             mountPath: /set
     containers:
     - image: nginx
       name: serve
       volumeMounts:
         - name: storage
           mountPath: /usr/share/nginx/html
     dnsPolicy: ClusterFirst
     restartPolicy: Always
     volumes:
       - name: storage
         emptyDir: {}
   status: {}

4. Take stew pod created from demeter namespace. Export port 80 of nginx container.

   Solution

   apiVersion: v1
   kind: Pod
   metadata:
     creationTimestamp: null
     labels:
       run: stew
     name: stew
     namespace: demeter
   spec:
     initContainers:
       - image: busybox
         name: setup
         command: ["sh","-c","echo 'this is nginx index page' > /set/index.html"]
         volumeMounts:
           - name: storage
             mountPath: /set
     containers:
     - image: nginx
       name: serve
       volumeMounts:
         - name: storage
           mountPath: /usr/share/nginx/html
       ports:
         - containerPort: 80
     dnsPolicy: ClusterFirst
     restartPolicy: Always
     volumes:
       - name: storage
         emptyDir: {}
   status: {}

5. check IP of stew pod and request it at port 80. Run a temporary busybox pod to perform that.

   Solution

   # check ip of the stew pod
   k get po stew -o wide
   
   # make request on port 80
   wget -qO- <IP>